L4V15 Posted December 5, 2012 Share Posted December 5, 2012 Hi chaps. Been meaning to post this question for a while. Recently my standard exhaust broke on my 300 revup. Obviously that trashed the fuel economy for the week or so that it was snapped. I have since had a cat-back true dual system fitted. I've had the exhaust on a month or two and I think the fuel economy is only very slightly better than it was with a snapped exhaust. I'm almost certain it's worse than it was standard. Saying that though the fuel economy on this revup Zed has never been as good as it was on my old 54 plate Zed. I feel it's a good 5 or so mpg down from what it should be. Is there anything I can check for which may be causing poor MPG? It's had a recent full service so it's nothing like that. Is it possible that a performance exhaust could make economy worse? I would imagine it to improve if anything providing driving style stays the same? Would an uprev remap improve the efficiency and mpg? I'm not hugely worried about I just thought id ask the question. If thats the MPG then so be it. I just find it odd that it's worse than my older pre-facelift Zed. Cheers Steve Quote Link to comment Share on other sites More sharing options...
Dblock Posted December 5, 2012 Share Posted December 5, 2012 Plug in a reader to check lambda sensors are still ok. Quote Link to comment Share on other sites More sharing options...
rtbiscuit Posted December 5, 2012 Share Posted December 5, 2012 could also be that its cold Quote Link to comment Share on other sites More sharing options...
Zugara Posted December 5, 2012 Share Posted December 5, 2012 If its any help, my 370 has gone down from circa 21 mpg to 13 mpg. I fitted spacers to the rears on Saturday and since then fuel economy has dropped like a stone, and its cold weather, wonder if it coincidental but it's shocking! Quote Link to comment Share on other sites More sharing options...
L4V15 Posted December 5, 2012 Author Share Posted December 5, 2012 If its any help, my 370 has gone down from circa 21 mpg to 13 mpg. I fitted spacers to the rears on Saturday and since then fuel economy has dropped like a stone, and its cold weather, wonder if it coincidental but it's shocking! Hell! Surely there must be something up with that? I'll get the lambda sensors checked out. Quote Link to comment Share on other sites More sharing options...
Sam Mcgoo Posted December 5, 2012 Share Posted December 5, 2012 The cool, dense, moist air of late will make a fair difference to your mpg as more air needs more fuel, you've probably noticed it feels a bit quicker too. That, coupled with the fact that you've got a shiny new exhaust that you like the sound of....leading to you putting your foot down a bit more and revving it a bit higher will probably be the cause. Quote Link to comment Share on other sites More sharing options...
smudgedon Posted December 6, 2012 Share Posted December 6, 2012 The cool, dense, moist air of late will make a fair difference to your mpg as more air needs more fuel, you've probably noticed it feels a bit quicker too. That, coupled with the fact that you've got a shiny new exhaust that you like the sound of....leading to you putting your foot down a bit more and revving it a bit higher will probably be the cause. Agreed Quote Link to comment Share on other sites More sharing options...
spursmaddave Posted December 6, 2012 Share Posted December 6, 2012 The first aftermarket exhaust I fitted actually improved MPG slightly, once I had stopped ragging it to hear the note... Quote Link to comment Share on other sites More sharing options...
spursmaddave Posted December 6, 2012 Share Posted December 6, 2012 Have you done an ECU reset as it might have been running rich when you exhaust was knackered and not compensated back enough Quote Link to comment Share on other sites More sharing options...
L4V15 Posted December 6, 2012 Author Share Posted December 6, 2012 Yea I've done an ECU reset. Yea I know what you mean about nice sounding exhausts making you want to push the throttle but no it's not the case this time. Normally a decent exhaust and a good air filter has shown me better mpg in the past due more slightly better engine efficiency. Also I would think that the cold dense air would improve mpg if anything due to the higher oxygen/cubic capacity in the air. The car feels faster because it's working more efficiently. Therefore if you drive it no faster than normal you would get better MPG. More bang for your buck. Maybe I'm completely wrong. Saying that I expect the maf sorts it out so probably equals out either way. Would an uprev improve MPG then? Quote Link to comment Share on other sites More sharing options...
NeilMH Posted December 6, 2012 Share Posted December 6, 2012 Yea I've done an ECU reset. Yea I know what you mean about nice sounding exhausts making you want to push the throttle but no it's not the case this time. Normally a decent exhaust and a good air filter has shown me better mpg in the past due more slightly better engine efficiency. Also I would think that the cold dense air would improve mpg if anything due to the higher oxygen/cubic capacity in the air. The car feels faster because it's working more efficiently. Therefore if you drive it no faster than normal you would get better MPG. More bang for your buck. Maybe I'm completely wrong. Saying that I expect the maf sorts it out so probably equals out either way. Would an uprev improve MPG then? If I was you I would have a remap. Generally a remap will give you a small increase in mpg anyway but I would have one to optimise the running in relation to the new exhaust. Quote Link to comment Share on other sites More sharing options...
4RE Leather Posted December 7, 2012 Share Posted December 7, 2012 The cool, dense, moist air of late will make a fair difference to your mpg as more air needs more fuel, you've probably noticed it feels a bit quicker too. That, coupled with the fact that you've got a shiny new exhaust that you like the sound of....leading to you putting your foot down a bit more and revving it a bit higher will probably be the cause. Is that right Paul? You got a new Zorst! Quote Link to comment Share on other sites More sharing options...
L4V15 Posted December 30, 2012 Author Share Posted December 30, 2012 Cured! MAF needed a clean. Getting 34MPG on a run again now. Quote Link to comment Share on other sites More sharing options...
wizurd Posted December 30, 2012 Share Posted December 30, 2012 just wondered how do you clean the maf? my zed doesn't need it doing but think my fiesta will and im guessing what ever substance you use on one maf would be the same for most. Quote Link to comment Share on other sites More sharing options...
Sam Mcgoo Posted December 30, 2012 Share Posted December 30, 2012 Just give the filament a spray with some electrical contact cleaner and let it dry. Do Not touch it with anything though. (I've heard you can also use carb cleaner) Quote Link to comment Share on other sites More sharing options...
Dblock Posted December 30, 2012 Share Posted December 30, 2012 Just give the filament a spray with some electrical contact cleaner and let it dry. Do Not touch it with anything though. (I've heard you can also use carb cleaner) +1 it will dry itself. Quote Link to comment Share on other sites More sharing options...
Darren-B Posted December 30, 2012 Share Posted December 30, 2012 As others have mentioned, the cooler, denser air will make a difference, I don`t notice it in the zed, just fill her up when she gets low (about 250miles to a tank). But my derv is down about 8mpg since the outside temps have dropped. Only averaging 47mpg with my lead foot & 3ltr soot chucker Quote Link to comment Share on other sites More sharing options...
spursmaddave Posted December 30, 2012 Share Posted December 30, 2012 As others have mentioned, the cooler, denser air will make a difference, I don`t notice it in the zed, just fill her up when she gets low (about 250miles to a tank). But my derv is down about 8mpg since the outside temps have dropped. Only averaging 47mpg with my lead foot & 3ltr soot chucker +1 with my Derv, i'm barely getting 40mpg at the moment Quote Link to comment Share on other sites More sharing options...
spursmaddave Posted December 30, 2012 Share Posted December 30, 2012 (edited) Double post forum is fubar tonight.... Edited December 30, 2012 by spursmaddave Quote Link to comment Share on other sites More sharing options...
Darren-B Posted December 31, 2012 Share Posted December 31, 2012 As others have mentioned, the cooler, denser air will make a difference, I don`t notice it in the zed, just fill her up when she gets low (about 250miles to a tank). But my derv is down about 8mpg since the outside temps have dropped. Only averaging 47mpg with my lead foot & 3ltr soot chucker +1 with my Derv, i'm barely getting 40mpg at the moment how do you manage that David Hobbs? Quote Link to comment Share on other sites More sharing options...
ilogikal1 Posted December 31, 2012 Share Posted December 31, 2012 As others have mentioned, the cooler, denser air will make a difference, I don`t notice it in the zed, just fill her up when she gets low (about 250miles to a tank). But my derv is down about 8mpg since the outside temps have dropped. Only averaging 47mpg with my lead foot & 3ltr soot chucker +1 with my Derv, i'm barely getting 40mpg at the moment how do you manage that David Hobbs? He's not worked out how to change out of first gear yet. :wink: Quote Link to comment Share on other sites More sharing options...
spursmaddave Posted December 31, 2012 Share Posted December 31, 2012 As others have mentioned, the cooler, denser air will make a difference, I don`t notice it in the zed, just fill her up when she gets low (about 250miles to a tank). But my derv is down about 8mpg since the outside temps have dropped. Only averaging 47mpg with my lead foot & 3ltr soot chucker +1 with my Derv, i'm barely getting 40mpg at the moment how do you manage that David Hobbs? I normally only get 45mpg anyway It's not your average Derv :wink: you will have to see what you think sometime : Quote Link to comment Share on other sites More sharing options...
Darren-B Posted December 31, 2012 Share Posted December 31, 2012 Oh I forgot it was the F****** Rapid spec Quote Link to comment Share on other sites More sharing options...
spursmaddave Posted December 31, 2012 Share Posted December 31, 2012 Oh I forgot it was the F****** Rapid spec Not quite in the Darren-B sleeper league but not bad for a derv :wink: Quote Link to comment Share on other sites More sharing options...
cs2000 Posted December 31, 2012 Share Posted December 31, 2012 Just give the filament a spray with some electrical contact cleaner and let it dry. Do Not touch it with anything though. (I've heard you can also use carb cleaner) Just in-case anoyones wondering. you can also use carb cleaner on the MAF's. Just be a bit carefull as theyre generally very delecate and a full on jet from a spray can could damage them, try to do it a a distance or something and make sure its dry before refitting. Quote Link to comment Share on other sites More sharing options...
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